Crankcase ventilator



2% E1950 H. A. @ARLSQN E'TAL CRANKCASE VENTILATOR Filed June 21, 1946 F I G. I.

TO CRANKCASE F l G. 3.

- INVENTOR HAROLD ACARLSON KENN TH S. GRILLEAUX BY ATTO RN EY Patented July 25, 1 950 Harold A. Carlson,'University City, and Kenneth S. Grilleaux, St. Louis, Mo., assignors to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application June 21, 1946, Serial No. 678,402

This invention relates to crankcase ventilators for internal combustion engines.

In such an engine, suction of the induction conduit may be conveniently utilized to draw air through the crankcase and other engine spaces it is desired to ventilate. Since the suction in the intake conduit varies widely from its highest point with the throttle valve closed to its lowest value under full throttle operating conditions, the ventilating means should be variable to compensate for these differences. This is especially true since a ventilating passage which is adequate during substantially full throttle,- low suction operation, would seriously upset the idling and low speed operation of the engine. Furthermore, such a ventilating passage would substantially reduce the efiective suction during cranking with the carburetor choke valve closed so as to retard or possibly prevent starting of the engine. As far as. we are aware, no one, previously, has provided a crankcase ventilator designed to operate satisfactorily under varied conditions of both the choke and throttle valves.

Accordingly, it is an object of the present invention to provide an engine crankcase ventilator arranged to provide adequate ventilation under normal, low suction conditions without upsetting the functioning of the engine during idling and low speed operation and during cold starting and warm-up of the engine.

A more detailed object is to provide a crankcase ventilator of substantial capacity when relatively large quantities of air are being drawn into the engine, but of substantially reduced capacity under conditions when relatively smaller quantities of air are supplied.

These objects and other more detailed objects hereafter appearing are attained by the device illustrated in the accompanying drawings in which Fig. 1 is a side view and section showing a carburetor and portion of the intake manifold of an internal combustion engine.

Fig. 2 shows a detail of Fig. 1 with the ventila tor valves in different positions.

Fig. 3 is a detail section on line :33 of Fig. 1.

The carburetor in Fig. 1 includes a downdraft induction or mixture conduit 5 having a series of Venturi tubes 6 centrally mounted therein. The admission of air to the upper end of the conduit is controlled by a choke valve 1 operated by automatic choke mechanism including a coiled thermostat 8 for resiliently closing the choke when the temperature is low and a suction piston 4 Claims. (01. 123-419) Lil 9 which tends to open the choke against the thermostat as the engine suction increases. This form of choke control is disclosed and claimed in Patent No. 2,085,351 in the nameof Irven'E. Coifey. The discharge of mixture from the carburetor is controlled by a throttle valve I0 near the, lower end of conduit 5 and mounted on a shaft I I. A constant level chamber I2 is provided adjacent the mixture conduit and has a main metering orifice element I3 in the lower part thereof controlled by a metering pin [4 operated from the throttle through lever l5 and link is. Fuel is supplied to the mixture conduit through orifice element l3, main fuel nozzle I1 and idling passages l8 discharging through ports is located adjacent and posterior to throttle [0 when closed.

A tube 22 is connected at one end (not shown) to the engine space to be ventilated as, for instance, the crankcase or valve chamber, and extends through a ventilating valve body member 23, conveniently integral with the carburetor body, into the mixture conduit anterior to the throttle by means of aperture 24 in boss 25 which journals the enlarged end 26 of throttle shaft ll. Shaft end 26 has a sector 2'! cut out so as to form a plug valve for opening passage 2! to the interior of the mixture conduit after the throttle valve has been opened a predetermined, substantial amount. The plug valve closes the ventilating passage during idling and the early stages of part throttle operation.

A second plug valve 30 is received in an apertured portion 3| of valve body 23 and is rigidly connected to an arm 32 connected by a link 33 to an arm 34 rigid with choke shaft 35. Plug valve 30 is cut out, as at 36, so as to open passage 21 to tube 22 after the choke valve has been opened a predetermined substantial amount. Valve 30 willbe closed during cold starting when the choke valve is closed or only slightly open.

In order to provide for limited ventilation when either of the valves 26 or 30 is closed, a restricted by-pass an connects tube 22 and the mixture conduit posterior to throttle [3. This arrangement is such that during idling and early part throttle operation, the relative high engine suction will operate through restriction All to provide ventilation without seriously aifecting engine operation. This by-pass also operates during cranking when valve 30 is closed. Under normal temperature operations, valve 30 will be fully opened, as shown in Fig. 2 and, as the throttle valve is opened beyond a predetermined, substantially open position, throttle operated valve 26 will open rapidly to connect the ventilating passage to carburetor suction through port 21. Since the latter port is anterior to the throttle valve, the effective suction therein will vary with the-rate of air flow through the carburetor and speed of the engine. By-pass fill supplements ventilation during idling when relatively little suction is available through port 21. The main ventilating passage 22, 27 is of substantial proportions to provide for adequate ventilation under normal, high speed running conditions when large quantities of fumes may iorm in the engine spaces.

The invention may be modified as will occur to those skilled in the art and the exclusive use of all modifications as come within the scope of the appended claims is contemplated.

We claim:

1. In a crankcase ventilator for an internal combustion engine, an induction ccnduit'having choke and throttle valves therein, a ventilating passage for connection to an engine space to -.be ventilated and opening into said conduit, a pair of ventvalves controlling said passage, operative connections between .said choke and throttle valves and respectiveones ,of said vent valves to move said .vent valves simultaneously with movement of the choke and throttle whereby .the degree of restriction of said ventilating passage by the vent valves is dependent upon the relative positions .of said choke and throttle valves.

2. In a crankcase ventilator for an internal combustion .engine, an induction conduit having choke and throttle valves therein, a ventilating passage for connection to an engine space to be ventilated and opening into said conduit between said choke and throttle valves, vent valve means in said passage, independent operative connections between said choke and throttle .valves and said vent valve means for closing said valve means when either s'aid choke or said throttle valve is 4 closed said valve means and said operable connections being adapted and arranged in said passage for opening said passage only when both of said valves are substantially opened, and a restricted by-pass between said ventilating passage and said conduit posterior to said throttle for providing limited Ven ilation ,when either of said choke and throttle valves is closed.

3. In a crankcase ventilator for an internal combustion engine, an induction conduit having choke and throttle valves therein, a ventilation passage connecting the crankcase and said inductiqncor duit between said choke and throttle .valves, vent .valves arranged in said ventilating passage and controlling the flow therethrough, an operative connection between said choke valve and one of said .vent valves to move the same toward closed position upon closing movement of the choke, an operative connection between the throttle valve and another vent valve to move the ilatter toward closed position upon closing of the throttle, and a restricted passage connecting the ventilating passage with the induction passage .posterior to the throttle.

,4. The substance of claim 3 characterized in that the vent valves are both fully closed when the choke and throttle are in closed position.

' HARGID A. :CARLSON.

S. GRILLEAUX.

REFERENGES CITED The following eierences are of record in the fil n this Paten UNITED ewe s 'rs 

